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Commercial wood-burning stoves for large public saunas
31 kW of wood-fired output for rooms up to 1,270 cu ft. The Finnish commercial wood-burning standard for destination builds.
Pro 20 (WK200) and Pro 36 (WK360) are the commercial-scale wood-burning stoves Harvia builds for public saunas, resorts, and large communal installations. Pro 36 is the headline unit: 31 kW equivalent output, rooms up to 1,270 cubic feet, 132 lbs of stones stacked in three tiers, and a fire chamber that accepts firewood up to 15.3 inches long. These heaters end up in Nordic bathhouses, ski-town communal saunas, and destination wellness properties. The minimum ceiling spec is 81 inches — scaled for commercial rooms, not residential.
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Editorial status
SaunaNews is independent and not affiliated with Harvia. This page is maintained as a product record for news coverage and timeline context, not a sales page.
Last timeline mention: February 12, 2026 · Q4 2025 earnings call + press release — Muurame capacity, US distribution expansion
Fuel
Wood-burning
Output (Pro 36)
~31 kW equivalent
Room size
494 – 1,270 cu ft
Stone capacity
~132 lbs
Firewood length
Up to 15.3"
Min ceiling
81"
| Model | Power | Room size | Stones | Voltage | Notes |
|---|---|---|---|---|---|
| Pro 20 (WK200) | ~20 kW equivalent | 283 – 700 cu ft | ~88 lbs | — | — |
| Pro 36 (WK360) | ~31 kW equivalent | 494 – 1,270 cu ft | ~132 lbs | — | — |
From earnings calls, investor presentations, annual reports, and the Harvia product catalog.
2 of 2 quotes include a direct source link.
“Muurame factory, the world's largest heater and sauna component factory: over 150,000 heaters per year.”
“In 2023, manufacturing [of wood-burning heaters] was almost fully moved to Muurame.”
Practical guidance from specialty dealers, commercial installers, and long-term Harvia operators. Use these notes alongside the official manual.
Pro 36's 81-inch ceiling requirement comes from flue clearance and radiant heat distribution. In rooms with 78-inch ceilings you get hot spots at head height and insufficient steam at bench height. Spec Pro 20 (or Legend 240SL) instead if the ceiling can't clear 81 inches.
Both compete in the 700-1,200 cu ft range. Pro 36 has the larger fire chamber — fast heat-up, shorter recovery between sessions — but smaller stone capacity (132 lbs vs 450 lbs). Legend 240SL has the external wood-feed door that commercial operators prefer for safety. If the operator wants fast room turnaround, Pro 36 wins. If the operator values safety and consistent steam recovery across a long service day, Legend 240SL.
At 31 kW output, flue gas temperatures run 600-800°F during active burning. Single-wall pipe is not rated for that. Every commercial Pro 36 install requires full insulated Class A from heater collar to termination above the roof. Budget $2,500-$4,500 for the chimney package alone. Single-wall pipe on this output is code violation and fire hazard.
Pro 36 stones in commercial rooms running 12+ hours a day need full reload at 18-24 months. Elements below stone are fine — the reason is thermal cycling breaks the stones themselves. Budget the reload into operations schedule or the room loses steam output gradually without the operator noticing.
Commercial and destination wood-fired saunas, ski-town communal bathhouses, Nordic-inspired resort installs, large private cabin builds where the operator wants the Finnish commercial experience. Rooms 500+ cu ft with 81+ inch ceilings.
This is editorial analysis for context, not a purchase recommendation.
Images sourced from the Harvia Media Bank. Product photography, variant shots, technical diagrams, and installation references straight from Harvia Plc.
Media Bank of Harvia. Courtesy of Harvia Plc.
Warranty
2 years
Made in
Muurame, Finland
Launched
Long-running Pro series; current Pro 36 (WK360) is the current generation
Last Harvia mention
February 12, 2026
Q4 2025 earnings call + press release — Muurame capacity, US distribution expansion
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Product data is sourced from Harvia Plc investor materials, earnings call transcripts, harvia.com, and harviagroup.com. Quotes are attributed to specific sources when available. Field notes reflect installer and dealer experience and should be validated against local code and the latest Harvia manuals. SaunaNews is independent and not affiliated with Harvia Plc.
If you spot an error or outdated spec, contact the SaunaNews editorial team so the record can be corrected.